A network system using a conventional virtualization technology, by using a virtualization technology disclosed in Non-Patent Literature 1, generates slices that are virtual networks logically generated on a network infrastructure by virtually dividing hardware resources. By allocating services to the slices, the services can each be provided using networks of independent slices. Accordingly, in a case in which slices are allocated to services having various required conditions, the required conditions of each service can be easily satisfied, and the signaling processes and the like thereof can be reduced.